lock: block signal interrupt while making a lock file
On Windows where symlink isn't supported, util.makelock() could leave an empty
file if interrupted immediately after os.open(). This empty lock never dies
as it has no process id recorded.
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
# an interrupt may occur here
os.write(ld, info)
os.close(ld)
This was a long-standing bug of TortoiseHg which runs a command-server and
kills it by CTRL_C_EVENT, reported by random Windows users.
https://bitbucket.org/tortoisehg/thg/issues/4873/#comment-
43591129
At first, I tried to fix makelock() to clean up a stale lock file, which
turned out to be hard because any instructions may be interrupted by a
signal.
ld = None
try:
# CALL_FUNCTION # os.open(...)
# an interrupt may occur here
# STORE_FAST # ld = ...
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
os.write(ld, info)
...
return True
except:
if ld:
...
os.unlink(pathname)
return False
So I decided to block signals by temporarily replacing the signal handlers
so makelcok() and held = 1 will never be interrupted.
Many thanks to Fernando Najera for investigating the issue.
# win32text.py - LF <-> CRLF/CR translation utilities for Windows/Mac users
#
# Copyright 2005, 2007-2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''perform automatic newline conversion (DEPRECATED)
Deprecation: The win32text extension requires each user to configure
the extension again and again for each clone since the configuration
is not copied when cloning.
We have therefore made the ``eol`` as an alternative. The ``eol``
uses a version controlled file for its configuration and each clone
will therefore use the right settings from the start.
To perform automatic newline conversion, use::
[extensions]
win32text =
[encode]
** = cleverencode:
# or ** = macencode:
[decode]
** = cleverdecode:
# or ** = macdecode:
If not doing conversion, to make sure you do not commit CRLF/CR by accident::
[hooks]
pretxncommit.crlf = python:hgext.win32text.forbidcrlf
# or pretxncommit.cr = python:hgext.win32text.forbidcr
To do the same check on a server to prevent CRLF/CR from being
pushed or pulled::
[hooks]
pretxnchangegroup.crlf = python:hgext.win32text.forbidcrlf
# or pretxnchangegroup.cr = python:hgext.win32text.forbidcr
'''
from __future__ import absolute_import
import re
from mercurial.i18n import _
from mercurial.node import (
short,
)
from mercurial import (
registrar,
util,
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
configtable = {}
configitem = registrar.configitem(configtable)
configitem('win32text', 'warn',
default=True,
)
# regexp for single LF without CR preceding.
re_single_lf = re.compile('(^|[^\r])\n', re.MULTILINE)
newlinestr = {'\r\n': 'CRLF', '\r': 'CR'}
filterstr = {'\r\n': 'clever', '\r': 'mac'}
def checknewline(s, newline, ui=None, repo=None, filename=None):
# warn if already has 'newline' in repository.
# it might cause unexpected eol conversion.
# see issue 302:
# https://bz.mercurial-scm.org/302
if newline in s and ui and filename and repo:
ui.warn(_('WARNING: %s already has %s line endings\n'
'and does not need EOL conversion by the win32text plugin.\n'
'Before your next commit, please reconsider your '
'encode/decode settings in \nMercurial.ini or %s.\n') %
(filename, newlinestr[newline], repo.vfs.join('hgrc')))
def dumbdecode(s, cmd, **kwargs):
checknewline(s, '\r\n', **kwargs)
# replace single LF to CRLF
return re_single_lf.sub('\\1\r\n', s)
def dumbencode(s, cmd):
return s.replace('\r\n', '\n')
def macdumbdecode(s, cmd, **kwargs):
checknewline(s, '\r', **kwargs)
return s.replace('\n', '\r')
def macdumbencode(s, cmd):
return s.replace('\r', '\n')
def cleverdecode(s, cmd, **kwargs):
if not util.binary(s):
return dumbdecode(s, cmd, **kwargs)
return s
def cleverencode(s, cmd):
if not util.binary(s):
return dumbencode(s, cmd)
return s
def macdecode(s, cmd, **kwargs):
if not util.binary(s):
return macdumbdecode(s, cmd, **kwargs)
return s
def macencode(s, cmd):
if not util.binary(s):
return macdumbencode(s, cmd)
return s
_filters = {
'dumbdecode:': dumbdecode,
'dumbencode:': dumbencode,
'cleverdecode:': cleverdecode,
'cleverencode:': cleverencode,
'macdumbdecode:': macdumbdecode,
'macdumbencode:': macdumbencode,
'macdecode:': macdecode,
'macencode:': macencode,
}
def forbidnewline(ui, repo, hooktype, node, newline, **kwargs):
halt = False
seen = set()
# we try to walk changesets in reverse order from newest to
# oldest, so that if we see a file multiple times, we take the
# newest version as canonical. this prevents us from blocking a
# changegroup that contains an unacceptable commit followed later
# by a commit that fixes the problem.
tip = repo['tip']
for rev in xrange(repo.changelog.tiprev(), repo[node].rev() - 1, -1):
c = repo[rev]
for f in c.files():
if f in seen or f not in tip or f not in c:
continue
seen.add(f)
data = c[f].data()
if not util.binary(data) and newline in data:
if not halt:
ui.warn(_('attempt to commit or push text file(s) '
'using %s line endings\n') %
newlinestr[newline])
ui.warn(_('in %s: %s\n') % (short(c.node()), f))
halt = True
if halt and hooktype == 'pretxnchangegroup':
crlf = newlinestr[newline].lower()
filter = filterstr[newline]
ui.warn(_('\nTo prevent this mistake in your local repository,\n'
'add to Mercurial.ini or .hg/hgrc:\n'
'\n'
'[hooks]\n'
'pretxncommit.%s = python:hgext.win32text.forbid%s\n'
'\n'
'and also consider adding:\n'
'\n'
'[extensions]\n'
'win32text =\n'
'[encode]\n'
'** = %sencode:\n'
'[decode]\n'
'** = %sdecode:\n') % (crlf, crlf, filter, filter))
return halt
def forbidcrlf(ui, repo, hooktype, node, **kwargs):
return forbidnewline(ui, repo, hooktype, node, '\r\n', **kwargs)
def forbidcr(ui, repo, hooktype, node, **kwargs):
return forbidnewline(ui, repo, hooktype, node, '\r', **kwargs)
def reposetup(ui, repo):
if not repo.local():
return
for name, fn in _filters.iteritems():
repo.adddatafilter(name, fn)
def extsetup(ui):
# deprecated config: win32text.warn
if ui.configbool('win32text', 'warn'):
ui.warn(_("win32text is deprecated: "
"https://mercurial-scm.org/wiki/Win32TextExtension\n"))